Figure 1.

The experimental design. Trifolium repens ramet pairs with roots and shoots of similar size were grown so each of their roots was confronted with another root that belonged to either the same (SELF) or to another physiological individual of the same (NON-SELF) or of a different genotype (ALIEN). The ramet connections were either left INTACT or SEVERED shortly before the experiment. The arrow represents the growth direction of the stolon. By reversing the growth direction, a younger ramet always competes with an older ramet in a single pot. Different shades represent different genotypes.